Hey and hi Lawler;

No offense taken - I was just confused. Actually, my reference to Birmingham was an attempt to place our OP Craig. I know of a couple of Birminghams in USA, but unlikely to house any 2.7 diesel Jags.

Now it turns out that both you and Craig hail from the same slice of the UK.
Therefore you will be well placed to advise Craig what your experience is re fuel economy figures.

Cheers.

 

The STR fuel economy is good. For a 400HP car, it's very good. Right up until you drive it like you stole it.

The diesel's probably OK.

They're pretty heavy cars (for the UK), but then they are nice and solid, so at some point it's just physics.

 

The image you conjure up is even cooler than it reads! LOL ...
Hey JagV8, while fuel economy of itself is not a cliff-hanger, a mate and I recently conducted a tandem fill-to-fill test along one of our better highways - not all flat like your M1 but steady 110km/h stuff.

The two cars are identical model, year, 2.7TTD engine etc, even full tanks of premium diesel from the same bowser, but one vital difference - mine with all P Zeros on 18"x8" Mercurys - his with Michelin asymetrics on 20" aftermarket rims 9" front and 10" rear. Conditions hot and dry with little to no traffic. The divided motorway (Sydney to Newcastle) provided side by side or front to back cruise control driving that ruled out differing driving habits.

Two way results? Over 10% increase in fuel consumption for the wider tyre car. Not a surprise perhaps - we expected a difference and that is why we did the test - but the scale of difference was unexpected. We are planning to repeat with petrol burners as soon as we can source 2 or more identical cars.

Any thoughts, anyone?

 

If you want better mpg go for narrower tyres, within safe limits.

There are no flat M1 stretches worth mentioning within many miles of me - or at all, perhaps. Doesn't really matter as I'm not comparing mpg.

 

>"I'm guessing your from birmingham "

Ya, too many Birminghams in the English-speaking world. Easy to get confused.

Damn, everything around here is either an English-name, some Indian word, or a smattering of French names.

We even have a Worcester pronounced woost'Ah, a Leominster pronounced Leminster, and Haverhill pronounced HAvrill

But we also have a Lake Cochituate pronounced... of forget it.
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You dreamed of big star, he played a mean guitar...
He loved to drive his Jaguar
So welcome to the machine

 

>Ya, too many Birminghams in the English-speaking world. Easy to get confused.

And that's Boston as in the NEW England one, not that olde groddy one over the'ah
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Jaguar - it's not an automobile, it's a Motorcar

 

The test means absolutely nothing. Only way to test is use the 1 car and swap the wheels.

2 cars will have different fuel usage stats even if they are "identical"

 

Wow! Not being nasty here, but we are genuinely interested in why and how you can give such an apparently knowledgeable rebuff. Your unambiguous dismissal suggests you have some explanation - and evidence?

 

Them funny things that have pedals and a tiny seat to sit on .....I think they are called bikes ....they have very narrow wheels and tyres on the ones called "racers " because they are made to go fast ....
Narrow wheels ,less friction ,faster, less resistance ,less effort to pedal .......

 

Picking up my 07 STR this Saturday! It's a 3 hour drive home from the dealership so I'm curious to see what I will average (mpg) on the drive home! I will "TRY" to behave most of the time with the throttle, but I make no promises!!!

 

Driving on the hwy at low speeds 65 I probably can average 20mpg in my 05 str. 12-14 in the city. The str is not good on gas nomadder how u drive.

 

That is low, have you checked your fuel trims (LTFT)?

 

STR is a gas guzzler, i average 17-18 MPG on mine, and i drive conservatively and half of my driving is highway.

 

Mine does double that on the hway.

 

I think when I leave the dealership I'm going to pour some fuel injector cleaner in her! Won't hurt anything so why not!

 

Hey you bought the STR for fun! So have some while driving her home!!

You only live once. Anyone buying a STR is not really too concerned with the fuel cost.
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Agreed. But unexplained low figures make me wonder about.... an explanation.

 

Indeed. 12-14 and 20 are about 5-7 lower than what these cars normally get.

 

Sounds like its in need of a tune-up? Plugs, fuel filter, throttle body service, mass sensor cleaned! Air filter dirty/plugged? Sometimes it's the little things that are looked over far to often. I am an over maintainer of all my vehicles. Always have been always will be. But the throttle body service is a big help. Along with a good fuel injector bottle to put in the tank every 10k to 15k miles. Also my latest thing I have been doing to vehicles is cleaning the mass air sensor with mass cleaner. You will be amazed at a little oil or dirt or even dust that sticks on the resistor that once cleaned off frees up a little power, along with throttle respone. But most importantly mpg!

 

You can't compare mpg on two different vehicles, the key word being different.

Add other things like adaptive gearbox, miles on each engine, wear on each engine, air filter type and condition, engine oil type, frequency of changes, spark plugs condition and gap size, coil age and condition, injector age and condition, the type and condition of each wheel bearing, the condition of the breaking system eg slightly sticking caliper etc.., the oil in the diff, the camber of the wheels in fact the whole suspension setup, egr, dpf, the exhaust system etc, the list of differences that will give you different mpg figures goes on and on, after the car we then move on to driver differences, again the list is endless, therfore your results are meaning less. (I realise the diesels you were using don't have plugs and coils, I'm just listing some of the most common reasons for different fuel usage figures between vehicles of the same type)

To have a propper comparison, the test needs to be done on the 1 vehicle in near as possible identical conditions, which is impossible on public roads.